Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2529/00—Catalysts comprising molecular sieves
  • C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays

Definitions

• the invention relates to a process for the preparation of aromatic hydrocarbons and hydrogen from propane or from a hydrocarbon mixture which consists of more than 75% w paraffins with at most four carbon atoms in the molecule (C 4- paraffins) and of at least 50% w propane, using a crystalline silicate as the catalyst.
• the present invention therefore relates to a process for the preparation of aromatic hydrocarbons and hydrogen, in which propane or a hydrocarbon mixture which consists of more than 75% w C 4 -paraffins and at least 50% w propane is contacted at an elevated temperature and a pressure of between 5 and 10 bar with a crystalline silicate as hereinafter defined, in which the formula which gives the overall composition of the silicate, the value of y is at least 0.0065 and the silicate contains zinc as the promotor.
• the starting material should be propane or a hydrocarbon mixture which consists of more than 75% w C 4 -paraffins and at least 50% w propane.
• Suitable C 4 -paraffins are methane, ethane, propane, butane and isobutane.
• the starting material is a hydrocarbon mixture which comprises in addition to one or more C 4 -paraffins one or more other hydrocarbons, these other hydrocarbons may be, inter alia, monoolefins, diolefins or C 5 -paraffins.
• the preferred starting material is a hydrocarbon mixture consisting of more than 60% w propane. It is also preferred to use hydrocarbon mixtures consisting of less than 20% w methane and/or ethane.
• a very suitable feed for the present process is a hydrocarbon mixture consisting substantially of C 3 and C 4 paraffins which has been obtained as a by-product in mineral oil production.
• the process according to the invention is preferably carried out at a temperature of from 400° to 700° C. and particularly from 450° to 600° C., a pressure of from 6 to 9 bar and a space velocity of from 0.1 to 20 g.g. -1 .h -1 and particularly from 0.5 to 10 g.g -1 .h -1 .
• propane or a hydrocarbon mixture which consists of more than 75% w C 4 -paraffins and at least 50% w propane is converted into aromatic hydrocarbons and hydrogen by contacting this feed with a certain crystalline silicate.
• These crystalline silicates are characterized in that ater 1 hour's calcining in air at 500° C. they have the following properties:
• M H and/or alkali metal and/or alkaline-earth metal
• n is the valency of M and O ⁇ y ⁇ 0.1.
• the silicate should first be converted into the H-form. This conversion is effected by boiling the silicate calcined at 500° C. with 1.0 molar NH 4 NO 3 solution, washing with water, boiling again with 1.0 molar NH 4 NO 3 solution and washing, drying at 120° C. and calcining at 500° C.
• Table B The complete X-ray powder diffraction pattern of a typical example of a silicate suitable for use according to the invention is shown in Table B (radiation: Cu-K; wavelength: 0.15418 nm).
• the crystalline silicates which are used as the catalyst in the process according to the invention can be prepared starting from an aqueous mixture containing the following compounds: one or more compounds of an alkali- or akaline-earth metal (M), one or more compounds containing an organic cation (R) or from which such a cation is formed during the preparation of the silicate, one or more silicon compounds and one or more aluminum compounds.
• exemplary organic cations include, e.g., primary, secondary and tertiary alkyl amines and quaternary ammonium hydroxide.
• the preparation is performed by maintaining the mixture at elevated temperature until the silicate has been formed and, subsequently, separating the crystals of the silicate from the mother liquor.
• the various compounds should be present in the following ratio, expressed in moles of the oxides:
• n is the valency of M and p is the valency of R.
• the silicates it is preferred to start from the base mixture in which M is present in a sodium compound and R in a tetrapropylammonium compound.
• the value of y in the formula which gives the composition of the silicates can be regulated with the aid of the molar ratio of SiO 2 to Al 2 O 3 in the starting mixture, in the sense that silicates with a lower value for y are obtained according as the molar ratio of SiO 2 to Al 2 O 3 in the starting mixture is chosen higher.
• the silicates prepared as described above contain alkali metal and/or alkaline-earth metal ions and organic cations.
• the alkali metal and alkaline-earth metal ions can be replaced by other cations, such as hydrogen ions or ammonium ions.
• Organic cations can very conveniently be converted into hydrogen ions by calcining the silicates.
• the crystalline silicates which are used in the process according to the invention preferably have an alkali metal content of less than 0.1% w, and in particular of less than 0.01% w.
• the crystalline silicates may, if desired, be combined with a natural or synthetic binder material such as bentonite or kaolin.
• a silicate should be used which has zinc as the promotor.
• a preferred silicate is one which contains 0.05 to 20% w and particularly 0.1 to 5% w zinc.
• the incorporation of zinc into the silicate may be performed in various ways, for instance by ion exchange or by impregnation. It is preferred to use in the process a silicate in which the zinc incorporation was performed by impregnating the silicate with an aqueous solution of a zinc salt followed by drying and calcining of the impregnated material.
• the process according to the invention can very conveniently be carried out by conducting the feed in upward or downward direction through a vertically mounted reactor, in which a fixed or moving bed of the catalyst concerned is present.
• silicates A-C Three crystalline silicates (silicates A-C) were prepared by heating mixtures of SiO 2 , NaAlO 2 , NaOH and [(C 3 H 7 ) 4 N]OH in water in an autoclave under autogenous pressure for 24 hours at 150° C. After the reaction mixtures had cooled down the silicates formed were filtered off, washed with water until the pH of the wash water was about 8 and dried for two hours at 120° C. After 1 hour's calcining in air at 500° C. the silicates A-C had the following properties:
• silicate B 0.0038 M 2 O. 0.0038 Al 2 O 3 .SiO 2
• the silicates I-III were prepared from the silicates A-C, respectively, by boiling the materials calcined at 500 C. with 1.0 molar NH 4 NO 3 solution, washing with water, boiling again with 1.0 molar NH 4 NO 3 solution and washing, drying at 120° C. and calcining at 500° C.
• silicates 1-3 were prepared, which contain zinc.
• the preparation was effected by impregnating samples of the silicates I-III with an aqueous solution of zinc nitrates followed by drying and calcining of the impregnated material to convert the zinc primarily to the oxide.
• the silicates 1-3 had the following compositions:
• Silicate 2 2% w Zn on silicate II
• silicates 1-3 and silicate I were tested as catalyst for the preparation of aromatic hydrocarbons and hydrogen from propane.
• the test was carried out in a 50-ml reactor containing a fixed catalyst bed having a volume of 5 ml consisting of the silicate concerned.
• Propane was conducted over the catalyst at a temperature of 475° C. and a space velocity of 2 g propane/g silicate/h.
• Table D The following data are included in the table: ##EQU3##

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Hydrogen, Water And Hydrids (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 1979
  • 1979-03-14 NL NLAANVRAGE7902020,A patent/NL190066C/xx not_active IP Right Cessation
• 1980
  • 1980-02-19 CA CA000345949A patent/CA1144884A/en not_active Expired
  • 1980-02-28 US US06/125,734 patent/US4288645A/en not_active Expired - Lifetime
  • 1980-03-12 IT IT20553/80A patent/IT1140782B/it active
  • 1980-03-12 DE DE19803009495 patent/DE3009495A1/de active Granted
  • 1980-03-12 FR FR8005499A patent/FR2451354A1/fr active Granted
  • 1980-03-12 JP JP3043480A patent/JPS55124722A/ja active Granted
  • 1980-03-13 GB GB8008513A patent/GB2044290B/en not_active Expired

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